The listing or discussion of an apparently prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.
The present invention provides a process using renewable resources, such as, oils and/or fats, fatty acids, and fatty acid esters derived from plants and animals to produce ester polyols in essentially quantitative yields via the ozonolysis process. The ester polyols are very useful for the production of polyurethane-based coatings and foams, as well as, polyester applications.
Most of the current polyurethanes foams are produced from petroleum based polyol. It is desirable to replace a portion or all of the petroleum polyol with a polyol derived from a plant or animal source when producing polyurethane foams or coatings. Polyols derived from plant or animal sources are known as biopolyols. Palm oil, which is primarily composed of saturated and unsaturated fatty acids chains, is a potential precursor for the production of polyols by using these double bonds to introduce hydroxyl groups by a number of chemical processes. It is desirable that this hydroxyl functionality be primary rather than secondary to enhance polyol reactivity in the preparation of polyurethanes by reacting with isocyanates. Other examples of vegetable and animal fats include soybean oil, safflower oil, linseed oil, corn oil, sunflower oil, olive oil, canola oil, sesame oil, cottonseed oil, mustard oil, camelina oil, jatropha oil, peanut oil, coconut oil, rapeseed oil, Chinese tallow oil, tung oil, castor oil, algae oil, wheat germ oil, soya oil, hemp oil, fish oil, lard, tallow, or the like and a mixture thereof.
Byproducts of the above-mentioned oils and lipids, such as, palm fatty acid distillates (PFAD), palm kernel fatty acid distillates, fractionated palm fatty acid distillate, and fractionated palm kernel fatty acid distillate, fatty acids of soybean oil, palm fatty acid alkyl esters, alkyl esters of any biobased lipids, or the like, or a mixture, or a fraction thereof may be used as a source of fatty acids.
The use of natural oils to produce ester polyols has been disclosed in several patents. In the production of polyols, natural oils offer two reactive sites, the double bond of unsaturated fatty acids, and the carboxyl ester group linking the fatty acid to the glycerine. U.S. Pat. No. 7,125,950 describes a solvent free process for making a fatty acid polyester polyol composition useful for the preparation of polyurethanes via the transesterification process. In this patent, natural oil is reacted with a multifunctional hydroxyl compound in the presence of an alkali metal or alkaline earth metal base or salt catalyst in absence of a solvent. The hydroxyl content of the prepared composition depends on the amount of the multi-functional hydroxyl compound used in the preparation.
PCT Pub. No. WO2007027223 describes various solvent-based approaches to prepare product ester polyols from plant or animal sources. PCT Pub. No. WO2007027223 disclose the production of 1-monoglycerides, 2-monoglycerides and diglycerides from the ozonolysis of soybean oil in the presence of a variety of primary polyols such as glycerin and either Bronsted or Lewis acids as catalysts. The polyols are reacted with polyisocyanates, polyacids, or polyesters to produce polyurethane and polyester coatings. However, WO2007027223 does not disclose or suggest the use of branched primary polyols.
US Patent Application No. US 2006/0194974 described a method for making a modified triglyceride which comprises reacting vegetable oil with ozone in a reaction mixture in the presence of a hydroxylated compound and alkaline catalyst. The ozone and the vegetable oil react to cleave double bonds of fatty acid groups within the triglyceride and the hydroxylated compound, in the presence of the catalyst, is added to terminal carbons of the cleaved double bonds through an ester covalent bond.
There still is a need in this technical field for ester polyols with improved performance characteristics for rigid and flexible foams and polyurethane coatings. Ester polyols prepared from feedstock containing high amounts of saturated fatty acids tend to undergo significant phase separation, resulting in the precipitation of waxy solids. Such ester polyols may then require additional process steps to make them suitable for processing into more useful products like coatings and foams. It is thus desirable to further investigate methods for improving the preparation of preparing ester polyols, in particular ester polyol which may comprise high amounts of saturated fatty acids.